Accompanied with the thriving electronic industries in the 21st century, electronic products have become indispensible commodities in the daily life. Manufacturers in general develop electronic products by aiming for function versatility and high performance, and frequently integrate LED chips into these electronic products. As portable electronic products continue to increase in diversity and decrease in size and weight, heat conduction efficiency of electronic products is a focus that draws much attention.
Current LED chips, having high illumination intensity, are widely employed in applications of electronic devices including display backlight sources, small-sized projectors and illumination devices. Approximately 80% of energy of power inputted into an LED is converted into heat energy. In the event that a carrier board of an LED element fails to effectively radiate the heat, the temperature at an interface of the LED chip may rise. In addition to undesirably affecting the illumination strength, the heat may also accumulate to cause expansion of layered materials of the LED chip and thus damage the overall structure to even lead to a shortened lifecycle of the product. Further, since the excited light in the LED is diffused by radiation instead of being entirely scattered via the surface of the LED, unsatisfactory and ineffective light extraction is resulted.
Based on the above reasons, if the heat conduction efficiency of LEDs can be improved and undesirable influences of thermal expansion of LEDs can be mitigated or eliminated, and a structure with an overall design capable of enhancing the heat conduction efficiency can be provided, it is apparent that developments of the electronic industries can be in large promoted.
Graphene is commonly defined as a sheet in a one-atom thickness and consisted of carbon atoms having sp2 bonding. The carbon atoms are closely arranged into a benzene structure in beehive crystallized lattices. Such two-dimensional material presents an extremely high electrical stability and outstanding heat conductivity at a plane of a layered structure. A plurality of parallel graphene layers stacked on one another are formed by graphite. The application of graphene on different products and materials is currently an inevitable trend.
For example, the Taiwan Patent TW201217446 discloses a polymer resin composition, an insulation film manufactured using the polymer resin composition, and a method of manufacturing the insulation film. The above insulation film including graphene is applied to an electronic circuit board to reduce the coefficient of thermal expansion. For another example, the Taiwan Patent TW201220562 discloses a radiating substrate, a method for manufacturing the radiating substrate and a luminous element package with the radiating substrate. In the above disclosure, the radiating substrate includes a macromolecular resin and graphene distributed in the macromolecular resin, and dissipates heat generated by a predetermined heating element to the exterior. For another example, the Taiwan Patent TW201145474 discloses an electronic/optoelectronic heat dissipating device, in which graphene or a carbon nanotube (CNT) cooperates with a current semiconductor element (e.g., an LED optoelectronic element or an integrated circuit element) to serve for heat dissipation purposes. As such, overall heat dissipation efficiency can be enhanced through the high coefficient of thermal expansion and the even heat conductivity of the graphene or CNT.
However, the above solutions of heat dissipation materials offer solutions from only perspectives of heat conduction. That is to say, in addition to having high heat conductivity, if a composite material can also achieve heat conduction via other heat conduction means, products applying such composite material may further reduce the influences that thermal factors pose on the lifecycle and performance of the products.
Therefore, there is a need for such composite material.